This is a part of the LP3943 MFD driver. LP3943 can be used as a PWM generator, up to 2 channels.
* Two PWM generators LP3943 has 16 output channels. Two channels are configurable as PWM generators. * Supported PWM operations config, set_polarity, enable and disable * Manual polarity configuration No register exists for setting polarity. However, the value of duty can be calculated as following. PWM-inversed mode : duty = period - duty PWM-normal mode : input duty itself * Pin MUX configuration at each PWM operation - enable and disable * Register access through exported LP3943 MFD functions Signed-off-by: Milo Kim <[email protected]> --- drivers/pwm/Kconfig | 10 +++ drivers/pwm/Makefile | 1 + drivers/pwm/pwm-lp3943.c | 192 ++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 203 insertions(+) create mode 100644 drivers/pwm/pwm-lp3943.c diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index 75840b5..28a7668 100644 --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig @@ -81,6 +81,16 @@ config PWM_JZ4740 To compile this driver as a module, choose M here: the module will be called pwm-jz4740. +config PWM_LP3943 + tristate "LP3943 PWM support" + depends on MFD_LP3943 + help + Generic PWM framework driver for LP3943. It supports two PWM + controllers. + + To compile this driver as a module, choose M here: the module + will be called pwm-lp3943. + config PWM_LPC32XX tristate "LPC32XX PWM support" depends on ARCH_LPC32XX diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile index 77a8c18..db8e349 100644 --- a/drivers/pwm/Makefile +++ b/drivers/pwm/Makefile @@ -5,6 +5,7 @@ obj-$(CONFIG_PWM_ATMEL_TCB) += pwm-atmel-tcb.o obj-$(CONFIG_PWM_BFIN) += pwm-bfin.o obj-$(CONFIG_PWM_IMX) += pwm-imx.o obj-$(CONFIG_PWM_JZ4740) += pwm-jz4740.o +obj-$(CONFIG_PWM_LP3943) += pwm-lp3943.o obj-$(CONFIG_PWM_LPC32XX) += pwm-lpc32xx.o obj-$(CONFIG_PWM_MXS) += pwm-mxs.o obj-$(CONFIG_PWM_PCA9685) += pwm-pca9685.o diff --git a/drivers/pwm/pwm-lp3943.c b/drivers/pwm/pwm-lp3943.c new file mode 100644 index 0000000..33e63fa7 --- /dev/null +++ b/drivers/pwm/pwm-lp3943.c @@ -0,0 +1,192 @@ +/* + * TI/National Semiconductor LP3943 PWM driver + * + * Copyright (C) 2013 Texas Instruments + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; version 2. + */ + +#include <linux/err.h> +#include <linux/i2c.h> +#include <linux/mfd/lp3943.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/pwm.h> +#include <linux/slab.h> + +#define LP3943_MAX_DUTY 255 +#define LP3943_MIN_PERIOD 6250 +#define LP3943_MAX_PERIOD 1600000 +#define LP3943_NUM_PWMS 2 + +#define to_lp3943_pwm(_chip) container_of(_chip, struct lp3943_pwm, chip) + +struct lp3943_pwm { + struct pwm_chip chip; + struct lp3943 *l; + enum lp3943_pwm_output output[LP3943_NUM_PWMS]; + bool inversed[LP3943_NUM_PWMS]; +}; + +static int lp3943_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, + int duty_ns, int period_ns) +{ + struct lp3943_pwm *lp = to_lp3943_pwm(chip); + u8 reg_prescale; + u8 reg_duty; + u8 val; + int err; + + /* + * How to configure the LP3943 PWMs + * + * 1) Period = 6250 ~ 1600000 + * 2) Prescale = period / 6250 -1 + * 3) Duty = 'input duty'(normal) or 'period - duty'(inversed) + * + * Prescale and duty are register values + */ + + if (pwm->hwpwm == 0) { + reg_prescale = LP3943_REG_PRESCALE0; + reg_duty = LP3943_REG_PWM0; + } else if (pwm->hwpwm == 1) { + reg_prescale = LP3943_REG_PRESCALE1; + reg_duty = LP3943_REG_PWM1; + } else { + return -EINVAL; + } + + period_ns = clamp(period_ns, LP3943_MIN_PERIOD, LP3943_MAX_PERIOD); + val = (u8)(period_ns / LP3943_MIN_PERIOD - 1); + + err = lp3943_write_byte(lp->l, reg_prescale, val); + if (err) + return err; + + if (lp->inversed[pwm->hwpwm]) + val = (u8)((period_ns - duty_ns) * LP3943_MAX_DUTY / period_ns); + else + val = (u8)(duty_ns * LP3943_MAX_DUTY / period_ns); + + return lp3943_write_byte(lp->l, reg_duty, val); +} + +static int lp3943_pwm_set_polarity(struct pwm_chip *chip, + struct pwm_device *pwm, enum pwm_polarity polarity) +{ + struct lp3943_pwm *lp = to_lp3943_pwm(chip); + + if (polarity == PWM_POLARITY_INVERSED) + lp->inversed[pwm->hwpwm] = true; + else + lp->inversed[pwm->hwpwm] = false; + + return 0; +} + +static int lp3943_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct lp3943_pwm *lp = to_lp3943_pwm(chip); + const struct lp3943_reg_cfg *mux = lp->l->mux_cfg; + int offset = lp->output[pwm->hwpwm] - 1; + u8 val; + + if (pwm->hwpwm == 0) + val = LP3943_DIM_PWM0; + else if (pwm->hwpwm == 1) + val = LP3943_DIM_PWM1; + else + return -EINVAL; + + return lp3943_update_bits(lp->l, mux[offset].reg, mux[offset].mask, + val << mux[offset].shift); +} + +static void lp3943_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct lp3943_pwm *lp = to_lp3943_pwm(chip); + const struct lp3943_reg_cfg *mux = lp->l->mux_cfg; + int offset = lp->output[pwm->hwpwm] - 1; + u8 val; + + /* + * LP3943 outputs are open-drain, so the pin should be configured + * when the PWM is disabled. + * + * - inversed: output low + * - normal: output Hi-Z + */ + + if (lp->inversed[pwm->hwpwm]) + val = LP3943_GPIO_OUT_LOW << mux[offset].shift; + else + val = LP3943_GPIO_OUT_HIGH << mux[offset].shift; + + lp3943_update_bits(lp->l, mux[offset].reg, mux[offset].mask, val); +} + +static const struct pwm_ops lp3943_pwm_ops = { + .config = lp3943_pwm_config, + .set_polarity = lp3943_pwm_set_polarity, + .enable = lp3943_pwm_enable, + .disable = lp3943_pwm_disable, + .owner = THIS_MODULE, +}; + +static int lp3943_pwm_probe(struct platform_device *pdev) +{ + struct lp3943 *l = dev_get_drvdata(pdev->dev.parent); + struct lp3943_platform_data *pdata = l->pdata; + struct lp3943_pwm *lp; + int num_pwms = 0; + int ret; + + lp = devm_kzalloc(&pdev->dev, sizeof(struct lp3943_pwm), GFP_KERNEL); + if (!lp) + return -ENOMEM; + + if (pdata->pwm0 != LP3943_PWM_INVALID) + lp->output[num_pwms++] = pdata->pwm0; + + if (pdata->pwm1 != LP3943_PWM_INVALID) + lp->output[num_pwms++] = pdata->pwm1; + + lp->l = l; + lp->chip.dev = &pdev->dev; + lp->chip.ops = &lp3943_pwm_ops; + lp->chip.npwm = num_pwms; + + platform_set_drvdata(pdev, lp); + + ret = pwmchip_add(&lp->chip); + if (ret < 0) { + dev_err(&pdev->dev, "failed to add PWM chip, err:%d\n", ret); + return ret; + } + + return 0; +} + +static int lp3943_pwm_remove(struct platform_device *pdev) +{ + struct lp3943_pwm *lp = platform_get_drvdata(pdev); + return pwmchip_remove(&lp->chip); +} + +static struct platform_driver lp3943_pwm_driver = { + .probe = lp3943_pwm_probe, + .remove = lp3943_pwm_remove, + .driver = { + .name = "lp3943-pwm", + .owner = THIS_MODULE, + }, +}; +module_platform_driver(lp3943_pwm_driver); + +MODULE_DESCRIPTION("LP3943 PWM driver"); +MODULE_AUTHOR("Milo Kim"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:lp3943-pwm"); -- 1.7.9.5 Best Regards, Milo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
